Fixation System for Orthopedic Devices

ABSTRACT

A fixation system configured to releasably secure an orthopedic implant to a bone. The orthopedic implant has at least one lumen extending from a proximal portion to a distal portion configured to extend through cortical portions and into cancellous portions of the bone. The fixation system includes a flowable biomaterial that flows through the lumen into the cancellous portion of the bone in an expanded configuration with at least one dimension greater than a corresponding dimension on the orthopedic implant located generally along a pull-out direction of the orthopedic implant. An insert is positioned in the lumen and in engagement with the flowable biomaterial located in the cancellous portion of the bone, such that the orthopedic implant is detachable from the biomaterial in the cancellous portion of the bone to facilitate subsequent removal of the orthopedic implant from the bone.

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/658,182, entitled Fixation System for OrthopedicDevices, filed Oct. 23, 2012, which is a continuation-in-part of PCTapplication PCT/US12/43346, entitled System and Method for RepairingJoints filed Jun. 20, 2012, which claims the benefit of U.S. ProvisionalApplication No. 61/498,687, entitled Orthopedic Fixation System andMethod of Use, filed Jun. 20, 2011; U.S. Provisional Application No.61/515,009, entitled Orthopedic Fixation System and Method of Use, filedAug. 4, 2011; and U.S. Provisional Application No. 61/591,304, entitledFixation System and Method for Repairing Joints, filed Jan. 27, 2012,the disclosures of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present disclosure is directed to a fixation system used tosupplement the fixation of an orthopedic implant. The fixation systemincludes a fixation structure that is releasably secured to theorthopedic implant and embedded in cancellous bone by a biomaterial. Thebiomaterial is preferably a resorbable, bone-growth stimulatingcomposition that interacts with the cancellous bone to incorporate thefixation structure in the cancellous bone.

BACKGROUND OF THE INVENTION

A wide variety of implantable orthopedic implants and procedures areknown for stabilizing and securing fractures in bones, replacing damagedjoints, attaching tissue to bone, and the like. For example, fixationplates and intramedullary devices can be surgically positioned to spanthe fracture site. Intramedullary devices are also commonly used toattach replacement joints to long bones. A variety of orthopedicfasteners, such as screws, pins, and the like, are typically used tohelp secure these orthopedic implants to the bone.

The ability of orthopedic fasteners to resist loosening is related tobone quality (O. R. Zindric et al Clinical Orthopaedics (1986)203:99-112), while the holding power of an orthopedic fastenercorrelates with mineral density (T. C. Ryken et al Journal ofNeurosurgery (1995) 83:325-329). If the bone at the implantation site iscompromised, either before, such as due to osteoporosis, or as a resultof the implantation procedure, the surgeon may have limited options forsecuring the orthopedic implant.

Loosening and backing out of an orthopedic fasteners can result indecreased structural integrity of the bone. Once an orthopedic fastenermanages to work itself loose, wear and tear to the opening or space inthe bone within which it was received may prohibit securely refasteningthe orthopedic fastener in the bone. Adding more orthopedic fasteners tocompensate for the compromised bone complicates future revision orremoval, and may further weaken the bone. For example, the formation ofscrew holes in the cortical bone provides stress risers thatsubstantially increases the risk of bone re-fracture. Since orthopedicimplants interfere with revascularization in the bone it is preferred tominimize the number of such devices.

U.S. Pat. Nos. 7,789,901 and 8,241,340 (Froehlich) discloses anexpandable structure fixedly attached to a distal end of a bone anchor.The expandable structure is configured to expand when a filler materialis delivered through a fill port and into the expandable structure. Thedistal end of the bone anchor is embedded in the cured filler materialto form a permanent connection with the bone.

U.S. Pat. No. 7,377,934 (Lin et al.) discloses an implant for anchoringtissue to bone. The implant is filled with a pasty medicine and iscaused to expand to lodge in the bone. Sutures are fastened at one endto the implant such that the other end of the sutures extend out of thebone and are joined with the tissue.

U.S. Pat. No. 7,717,947 (Wilberg et al.) discloses a cannulated bonescrew with an axial bore and exit ports near the threads. Bone cement isinjected through the axial bore and flows out the exit ports topermanently anchor the bone screw in the bone. The bone cement islocated at the interface of the bone screw to the bone.

U.S. Pat. No. 7,488,320 (Middleton) discloses an anchor for anorthopedic implant similar to Wilberg with lumens for injecting bonecement. The bone cement forms an interlocking relationship withstructures and voids on a preformed element to permanently anchor thedevice in the bone. Once the injectable material is hardened, theanchors of Wilberg is permanently locked in position.

The strategies noted above rely on bone cement to augment pull outstrength. PMMA is exothermic upon polymerization and toxic monomers cancause bone necrosis, proliferation of fibrous tissue layers and otheradverse biological responses (H. C. M. Amstutz et al Clin. Orthop.(1992) 276:7-18 and J. G. Heller et al J. Bone J. Surg. [Am] (1996)78:1315-1321). Cement induced osteolysis or necrotic bone may impair thefixation and lead to eventual fastener loosening and failure. In thecase of failure it is often difficult to remove cement from the bone andit is usually associated with excessive damage to the surrounding bone.

In some cases an orthopedic implant may need to be adjusted or correctedafter the original implantation surgery is completed. Such revisions maybe necessitated by re-fracture, infection, deterioration of the bone,situations where the patient's subsequent growth requires revision ofthe implant so as not to impede proper growth, and the need to movecorrective forces of the orthopedic implant on an area or in anorientation that is different from what was originally needed. In thosecases, an adjustment, correction or other revision of the implantedorthopedic implant will require unlocking and removal of the orthopedicfasteners. Bone cement at the interface with the orthopedic fastenersgreatly complicates this procedure.

A number of cementless solutions have been proposed, such asinterlocking screws (B. E. McKoy, 47.sup.th Annual Meeting, OrthopaedicResearch Society, Feb. 25-28, 2001, Session 19, Bone Mechanics II) andbone screw anchors (B. E. McKoy and Y. H., An Journal of OrthopaedicResearch (2001) 19:545-547). Other bone implantation/fixation devicesand methods are known in the art, for example, U.S. Publication No.2004/0181225, U.S. Pat. No. 5,084,050, U.S. Pat. No. 5,720,753, U.S.Pat. No. 6,656,184, U.S. Pat. No. 6,517,542 and U.S. Pat. No. 6,835,206.Helical anchors are generally well known, for example, U.S. Pat. No.806,406, U.S. Pat. No. 3,983,736, U.S. Pat. No. 4,536,115, U.S. Pat. No.5,312,214, U.S. Pat. No. 6,276,883, U.S. Pat. No. 6,494,657 and U.S.Pat. No. 6,860,691. Furthermore, helically wound springs have beendescribed for use as tissue anchors (WO 01/08602) and helical coils havebeen described for use as surgical implants (U.S. Publication No.2004/0225361).

BRIEF SUMMARY OF THE INVENTION

The present disclosure is directed to a fixation system used tosupplement the fixation of an orthopedic implant. The optional fixationsystem includes a fixation structure that is inserted into thecancellous bone through a lumen in an orthopedic implant. The orthopedicimplant and fixation system are intended to be implanted in the patientand remain in the patient indefinitely. The orthopedic implant and thefixation structure are typically separate and discrete structures thatare releasably attached to permit future removal, revision, adjustment,and the like.

In many circumstances, the orthopedic implant is sufficiently secure inthe bone such that no further fixation assemblies are required. If,however, the surgeon determines that the orthopedic implant is notsufficient stable, either during the current procedure or during asubsequent procedure, the insert can optionally be removed to expose thelumen. The present fixation system is then implanted and coupled to theorthopedic implant. The present approach provide the surgeon additionalflexibility during the implantation procedure or during a laterrevision, without compromising the structural integrity of theorthopedic implant.

One embodiment is directed to a fixation system configured to releasablysecure an orthopedic implant to a bone. The orthopedic implant has atleast one lumen extending from a proximal portion to a distal portionconfigured to extend through cortical portions and into cancellousportions of the bone. The fixation system includes at least oneexpandable member configured to be inserted through the lumen andpositioned in the cancellous bone near the distal portion of theorthopedic implant. The expandable member includes at least one chamber.A flowable biomaterial is delivered through the lumen and inflates theexpandable member to an expanded configuration located in the cancellousbone. The expanded configuration includes at least one dimension greaterthan a corresponding dimension on the orthopedic implant to secure theorthopedic implant in the bone. An insert is secured in the lumen toreleasably attach the fixation system to the orthopedic implant, suchthat the expandable member is detachable from the orthopedic implant tofacilitate subsequent removal of the orthopedic implant from the bone.The biomaterial preferably acts to incorporate the expandable memberinto the cancellous bone.

The present fixation system provide the surgeon with the option toaugment the fixation of an orthopedic implant, without compromisingstructural integrity of the implant. As a result, the breaking angle,torsion strength, torsion yield strength, insertion torque, self-tappingforce, and maximum torque of the orthopedic implant combined with theinsert, as measured according to ASTM standard F543-07—StandardSpecification and Test Methods for Metallic Bone Screws, are comparableto the same orthopedic implant without the lumen and insert. Properlyengineered, the breaking angle, torsion strength, torsion yieldstrength, insertion torque, self-tapping force, and maximum torque ofthe orthopedic implant combined with the insert are greater than thesame orthopedic implant without the lumen and insert.

The present fixation system increases the pull out strength of theorthopedic implant, as measured ASTM standard F543-02 Annex A3 “TestMethod for Determining the Axial Pullout Strength of Medical BoneScrews, by at least 20%, or at least 40%, or at least 70%, relative tothe orthopedic implant alone.

In one embodiment, the expandable member is a porous structure withopenings sized to permit intimate contact between the biomaterial andthe cancellous bone. The expandable member is optionally apre-determined volume and shape.

In one embodiment, the expandable member includes a neck portionconfigured to be secured to the orthopedic implant by the insert. Theneck portion is preferably configured to be compressively engagedbetween the insert and an inside surface of the lumen. The expandablemember and the neck portion are optionally a unitary woven structure.The insert is preferably the same insert used to seal the lumen in theorthopedic implant. A sleeve can optionally be used to guide the insertinto the neck portion.

The biomaterial is preferably a curable biomaterial. A delivery tube isoptionally configured to be inserted in the lumen and fluidly coupled tothe expandable member to deliver a flowable biomaterial to the chamber.At least one check-valve assembly is optionally provided on theexpandable member to receive the delivery tube and to retain theflowable biomaterial in the chamber after the delivery tube is removed.The biomaterial is preferably a resorbable, bone-growth stimulatingcomposition that interacts with the cancellous bone through openings inthe first expandable member. In another embodiment, the lumen of theorthopedic implant is used to deliver the biomaterial to the expandablemember.

The delivery tube can be used to force the expandable member into thecancellous bone. In another embodiment, an inflatable device is providedto be inserted through the lumen in the orthopedic implant and expandedto prepare the cancellous bone to receive the expandable member. Abiomaterial delivery system is provided to fluidly couple with aproximal end of the delivery tube to delivery the biomaterial underpressure to the chamber in the expandable member.

The expandable member optionally includes a plurality of fluidly coupledexpandable members. A plurality of discrete expandable members ofdifferent sizes and shapes can be provided in a kit to provide thesurgeon with options depending on the application.

Another embodiment is directed to an orthopedic implant configured to beimplanted in a bone. The orthopedic implant includes at least one lumenextending from a proximal portion to a distal portion configured toextend through cortical portions and into cancellous portions of thebone. At least one fixation structure is configured to be insertedthrough the lumen and positioned in the cancellous bone near the distalportion of the orthopedic device. A flowable biomaterial configured toflow through the lumen to the cancellous bone and into engagement withthe fixation structure. The flowable biomaterial and/or the fixationstructure include at least one dimension greater than a correspondingdimension on the orthopedic device to secure the orthopedic device inthe bone. An insert is configured to be secured in the lumen toreleasably attach the fixation structure to the orthopedic device. Thefixation structure is detachable from the orthopedic implant tofacilitate subsequent removal of the orthopedic implant from the bone.In one embodiment, the biomaterial serves as the insert.

The fixation structure can be configured as one or more filaments,ribbon shaped structure, a sling, a braided structure, and the like. Thefixation structure can be made from any of the material disclosedherein, including mono-filaments, woven or non-woven materials, mesh,porous and non-porous sheet materials, fabrics, suture material, and thelike.

Another embodiment is directed to an orthopedic implant configured to beimplanted in a bone. The orthopedic implant includes at least one lumenextending from a proximal portion to a distal portion configured toextend through cortical portions and into cancellous portions of thebone. A fixation system is provided that includes at least oneexpandable member configured to be inserted through the lumen andpositioned in the cancellous bone near the distal portion of theorthopedic device. The expandable member includes at least one chamber.A delivery tube is configured to be inserted in the lumen and fluidlycoupled to the expandable member to deliver a flowable biomaterial tothe chamber. A flowable biomaterial is provided that flows through thedelivery tube and inflates the expandable member to an expandedconfiguration located in the cancellous bone. The expanded configurationincludes at least one dimension greater than a corresponding dimensionon the orthopedic device to secure the orthopedic device in the bone. Aninsert is secured in the lumen to releasably attach the fixation systemto the orthopedic device, such that the expandable member is detachablefrom the orthopedic implant to facilitate subsequent removal of theorthopedic implant from the bone.

The insert is preferably configured to seal the lumen in the orthopedicdevice when the fixation system is not in use. The orthopedic device canbe a bone screw, bone pin, intramedullary implant, acetabular implant,glenoidal implant, bone plate, or bone anchor.

The present disclosure is also directed to a method of implanting anorthopedic implant in a bone. The method includes implanting anorthopedic implant in the bone such that a proximal portion of theorthopedic implant is accessible, and a distal portion of the orthopedicimplant extends through cortical portions and into cancellous portionsof the bone. The surgeon then evaluates fixation of the orthopedicimplant. If additional fixation is indicated, an insert is removed toexpose at least one lumen extending from the proximal portion to thedistal portion. At least one expandable member is inserted through thelumen and positioning the expandable member in the cancellous bone. Aflowable biomaterial is delivered through the lumen and into theexpandable member located in the cancellous bone. The expandable memberis expanded to an expanded configuration with at least one dimensiongreater than a corresponding dimension on the orthopedic implant in thebone. The insert is secured in the lumen to releasably attach thefixation system to the orthopedic implant, such that the expandablemember is detachable from the orthopedic implant to facilitatesubsequent removal of the orthopedic implant from the bone.

The method includes bringing the biomaterial into intimate contact withthe cancellous bone through openings in the expandable member. A neckportion on the expandable member is used to secure the fixation systemto the orthopedic implant.

In one embodiment, an inflatable device is inserted through the lumenand into the cancellous bone. The inflatable device is inflated toprepare the cancellous bone to receive the expandable member.

Another embodiment is directed to fixation system configured toreleasably secure an orthopedic implant to a bone. The orthopedicimplant has at least one opening adjacent a bore formed in a corticalportions of the bone. The fixation system includes at least oneexpandable member configured to be inserted through the bore and intocancellous portion of the bone. A flowable biomaterial is deliveredthrough the opening to inflate the expandable member to an expandedconfiguration located in the cancellous bone. The expanded configurationincludes at least one dimension greater than a corresponding dimensionof the bore. A fastener releasably attach the expandable member to theorthopedic implant, such that the expandable member is detachable fromthe orthopedic implant to facilitate subsequent removal of theorthopedic implant from the bone.

Another embodiment is directed to a fixation system for securing tissueto bone. At least one expandable member is configured to be insertedthrough a bore to a cancellous portion of the bone. The expandablemember includes a neck portion configured to extend through the bore andaway from the bone. A flowable biomaterial is delivered through the boreto inflate the expandable member to an expanded configuration whilelocated in the cancellous bone. The expanded configuration includes atleast one dimension greater than a corresponding dimension of the bore.At least one check-valve assembly is located on the expandable memberconfigured to retain the flowable biomaterial in the expandable member.One or more fasteners are used to secure the neck portion to the tissue.This embodiment is preferably used in combination with suture anchors.The suture anchor permits the surgeon to tension the tissue as desiredbefore attaching the neck portion. The suture anchor can optionally beinserted in the bore with the neck portion.

The present disclosure is also directed to a method of securing tissueto bone. A bore is formed in the bone and a cavity is prepared in thebore. At least one expandable member is positioned in the cavity so aneck portion on the expandable member extends through the bore and awayfrom the bone. A flowable biomaterial is delivered through the openingto inflate the expandable member to an expanded configuration whilelocated in the cancellous bone. The expanded configuration includes atleast one dimension greater than a corresponding dimension of the bore.The neck portion is secured to the tissue using one or more fasteners.

The neck portion can be located along two opposing surfaces of thetissue. The present embodiment can be used with suture anchors totension the tissue before attaching the neck portion.

The present disclosure is also directed to a fixation system configuredto releasably secure an orthopedic implant to a bone. The orthopedicimplant has at least one lumen extending from a proximal portion to adistal portion configured to extend through cortical portions and intocancellous portions of the bone. The fixation system includes a flowablebiomaterial configured to flow through the lumen into the cancellousportion of the bone in an expanded configuration comprising at least onedimension greater than a corresponding dimension on the orthopedicimplant located generally along a pull-out direction of the orthopedicimplant. An insert is configured to be inserted through the lumen andinto engagement with the flowable biomaterial located in the cancellousportion of the bone, such that the orthopedic implant is detachable fromthe biomaterial in the cancellous portion of the bone to facilitatesubsequent removal of the orthopedic implant from the bone. At least oneexpandable member is optionally positioned in the cancellous bone near adistal portion of the lumen configured to receive the biomaterial andexpand to the expanded configuration in the cancellous bone.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 illustrates an orthopedic implant for use with a fixation systemin accordance with an embodiment of the present disclosure.

FIGS. 2A through 2H illustrate a method of securing an orthopedicimplant with a fixation system in accordance with an embodiment of thepresent disclosure.

FIG. 3 is a schematic illustration of a kit for a fixation system inaccordance with an embodiment of the present disclosure.

FIGS. 4A through 4C illustrate methods of preparing cancellous bone toreceive a fixation system in accordance with an embodiment of thepresent disclosure.

FIG. 5 illustrates an alternate fixation system with engagement featuresin accordance with an embodiment of the present disclosure.

FIG. 6 illustrates an alternate structure for securing a fixation systemto an orthopedic implant in accordance with an embodiment of the presentdisclosure.

FIGS. 7A through 7C illustrate an alternate orthopedic implant with afixation system in accordance with an embodiment of the presentdisclosure.

FIGS. 8A and 8B illustrate an alternate method of securing a fixationsystem to an orthopedic implant in accordance with an embodiment of thepresent disclosure.

FIG. 8C illustrates an alternate method of securing a fixation system toan orthopedic implant in accordance with an embodiment of the presentdisclosure.

FIG. 8D illustrates an alternate insert for securing a fixation systemto an orthopedic implant in accordance with an embodiment of the presentdisclosure.

FIGS. 9A and 9B illustrate an insert secured at both ends of anorthopedic implant in accordance with an embodiment of the presentdisclosure.

FIG. 10 illustrates an acetabular orthopedic implant with a fixationsystem in accordance with an embodiment of the present disclosure.

FIG. 11 illustrates a glenoidal orthopedic implant with a fixationsystem in accordance with an embodiment of the present disclosure.

FIGS. 12A and 12B illustrate a method of deploying a fixation systemwith a plurality of expandable members in accordance with an embodimentof the present disclosure.

FIG. 13 illustrates a modular fixation system with a plurality ofexpandable members in accordance with an embodiment of the presentdisclosure.

FIG. 14 illustrates a radial distal fraction plate with a fixationsystem in accordance with an embodiment of the present disclosure.

FIGS. 15 and 16 illustrate a bone anchor with a fixation system inaccordance with an embodiment of the present disclosure.

FIGS. 17A and 17B illustrate an alternate bone anchor with a fixationsystem in accordance with an embodiment of the present disclosure.

FIGS. 18A and 18B illustrate a combination bone anchor-tissue anchor andfixation system in accordance with an embodiment of the presentdisclosure.

FIG. 19 illustrates an adjustable tissue anchor and fixation system inaccordance with an embodiment of the present disclosure.

FIGS. 20A through 20C illustrate use of a sleeve to guide an insert intoengagement with an expandable member in accordance with an embodiment ofthe present disclosure.

FIGS. 21A through 21C illustrate the use of the biomaterial as an insertto secure a fixation system to an orthopedic implant in accordance withan embodiment of the present disclosure.

FIG. 22 is a flow chart of a method of implanting an orthopedic implantin a bone in accordance with an embodiment of the present disclosure.

FIGS. 23A and 23B illustrate an alternate insert for securing anexpandable member to an orthopedic implant in accordance with anembodiment of the present disclosure.

FIGS. 23C and 23D illustrate another alternate insert for securing anexpandable member to an orthopedic implant in accordance with anembodiment of the present disclosure.

FIGS. 24A through 24C illustrate an alternate fixation structure for anorthopedic implant in accordance with an embodiment of the presentdisclosure.

FIGS. 25A and 25B illustrate an alternate fixation structure for anorthopedic implant in accordance with an embodiment of the presentdisclosure.

FIGS. 25C and 25D illustrate a fixation structure without an expandablemember in accordance with an embodiment of the present disclosure.

FIG. 26A illustrates and insert and fixation structure for use with anorthopedic implant in accordance with an embodiment of the presentdisclosure.

FIG. 26B illustrates an orthopedic implant with the insert and fixationstructure of FIG. 26A.

FIGS. 27A through 27E illustrates a bone anchor with a fixationstructure in accordance with an embodiment of the present disclosure.

FIGS. 28A through 28C illustrates an alternate bone anchor with afixation structure in accordance with an embodiment of the presentdisclosure.

FIG. 29A through 29C illustrates a bone plate secured with a fixationstructure in accordance with an embodiment of the present disclosure.

FIG. 30 illustrates an alternate bone plate secured with a fixationstructure in accordance with an embodiment of the present disclosure.

FIGS. 31A through 31C illustrates an alternate fixation structure inaccordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a side view of an orthopedic implant 50 configured for usewith an optional fixation system 98 (see FIG. 2E) in accordance with anembodiment of the present disclosure. The orthopedic implant 50 ispreferably a discrete, independently functioning structure that can beimplanted in a patient, without the fixation system 98. The fixationsystem 98 is typically included only on an as needed basis as determinedby the surgeon. The present fixation system functions as an optionaladd-on for a variety of orthopedic implants.

In the illustrate embodiment, the orthopedic implant 50 is a cannulatedbone screw 52 having a head 54, a shank 56 with threads 58. Lumen 60extends from the head 54 to distal end 62. Insert 64 includes threads 66configured to engage with internal threads 68 in the head 54. In theillustrated embodiment, distal end 70 of the lumen 60 includes taperedportion 72 that corresponds with tapered portion 74 at the distal end 76of the insert 64. When located in the orthopedic implant 50, the insert64 substantially seals the lumen 60 (see FIG. 2). Cannulated bone screwsused for common orthopedic applications typically have diameters in therange of about 2.5 millimeters to about 8 millimeters, with a lumendiameter in the range of about 1.3 millimeters to about 3.5 millimeters.Length of the bone screw varies with application.

The orthopedic implant 50 can be constructed from a variety ofbiocompatible materials such as titanium, titanium alloys, 316Lstainless steel, cobalt chrome alloys, and non-absorbable and absorbablepolymers as known in the art. The implantable implant 50 may be coatedwith a porous and bioactive material or a combination thereof to allowbone growth onto the device and to promote bone growth into any notchesor other openings or spaces surrounding the device (collectively bonein-growth). For example, one or more of hydroxyapatite, bone morphogenicprotein-2 (BMP-2), retinoic acid and biophosphonates may enhance bonein-growth. Alternatively, the surface of the device could be porous tosimilarly encourage bone growth and promote fixation of the devicewithin the bone.

FIGS. 2A through 2H illustrate a sequence for using the orthopedicimplant 50 in accordance with an embodiment of the present disclosure.FIG. 2A illustrates the bone screw 52 extending through cortical bone 80and into the considerably softer and sponge-like inner cancellous bone82 of the bone 84. The insert 64 reinforces the cannulated bone screw 52so that it has comparable torsion and bending strength of anon-cannulated bone screw. In particular, the breaking angle, torsionstrength, torsion yield strength, insertion torque, self-tapping force,and maximum torque of the bone screw 52 combined with the insert 64, asmeasured according to ASTM standard F543-07—Standard Specification andTest Methods for Metallic Bone Screws, are comparable to the same bonescrew 52 without the lumen 60 and the insert 64.

In many circumstances, the bone screw 52 is sufficiently secure in thebone 84 such that no further fixation assemblies are required. If,however, the surgeon determines that the bone screw 52 is not sufficientstable, either during the current procedure or during a subsequentprocedure, the insert 64 can optionally be removed to expose the lumen60 as illustrated in FIG. 2B. The present approach provides the surgeonadditional flexibility during the implantation procedure or during alater revision, without compromising the structural integrity of theorthopedic implant 50.

FIG. 2C illustrates inserting fixation structure 89 through the lumen 60and into the cancellous bone 82. The fixation structure can be anybiocompatible material that is designed to be retained in cancellousbone by a biomaterial, such as the expandable member 90 discussedherein. In many applications, the fixation structure substantiallyretains the biomaterial, while permitting intimate contact with thecancellous bone. In applications where flow of the biomaterial is not aconcern, a cavity in the cancellous bone can be used to retain thebiomaterial and the fixation structure can assume any configurationsuitable for engaging with the biomaterial, such as for example, asling, a filament, a barbed structure, and the like. The fixationstructure is embedded in the biomaterial and the biomaterial preferablycreates a mechanical interlock with the bone. In some embodiments, thebiomaterial bonds with, or is incorporated into, the bone, increasingthe fixation strength.

In the illustrated embodiment, the fixation structure 89 is a flexibleexpandable member 90 supported by delivery tube 88. Stop 92 is engagedwith threads 94 at proximal end 96 of the delivery tube 88 to limit howfar the expandable member 90 is inserted into the cancellous bone 82. Ifnecessary, the proximal end 96 of the delivery tube 88 can be gentlytapped with a hammer until the stop 92 engages the head 54. For use in abone screw, the delivery tube 88 has an inside lumen typically with adiameter in the range of about 1.0 millimeters to about 3.0 millimeters.For use in an intermedullary application, the delivery tube 88 can havea significantly larger lumen diameter.

As illustrated in FIG. 2C, the delivery tube 88 is preferably advancedbeyond the distal end 62 of the bone screw 52 in order to position theexpandable member 90 in the cancellous bone 82, and to position theexpandable member 90 relative to the bone screw 52. In alternateembodiments, a cavity is formed in the cancellous bone 82 to facilitiespositioning the expandable member 90 (see e.g., FIGS. 4A through 4C).

The delivery tube 88 may be constructed from a variety of metal orpolymeric materials and can be flexible or rigid depending on theapplication. In one embodiment, the delivery tube 88 has sufficientcolumn stiffness to displace and compress the cancellous bone 82. Inanother embodiment, a stylet is inserted into the delivery tube 88 toaugment the column stiffness of the delivery tube 88 during insertioninto the cancellous bone 82, and then subsequently removed to permitdelivery of the biomaterial 100.

As illustrated in FIG. 2D, the delivery tube 88 is preferably retracteda sufficient amount so that the distal end 102 of the delivery tube 88does not interfere with the delivery of the biomaterial 100. Thebiomaterial 100 is then delivered through the delivery tube 88 to fillchamber 104 and at least partially inflate the expandable member 90. Inthis context, the term inflate generally means to distend, swell, orexpand a flexible structure with a fluid.

In the preferred embodiment, the delivery pressure of the biomaterial100 is sufficient to compress the adjacent cancellous bone 82 as theexpandable member 90 is filled. In the expanded configuration 108illustrated in FIG. 2D, the expandable member 90 and the biomaterial 100preferably substantially fill, and conform to, the shape of, the cavity106.

In one embodiment, the expandable member 90 has a shape generallyconforming to the shape of the cavity 106 and the biomaterial 100. Inanother embodiment, the expandable member 90 is embedded in thebiomaterial 100, but does not have a shape that corresponds to the shapeof the cavity 106.

Once delivery of the biomaterial 100 is completed, the delivery tube 88is withdrawn, as illustrated in FIG. 2E. Neck portion 110 of theexpandable member 90 is positioned in the lumen 60 at the taper 72. Thefixation system 98 is now ready to be secured to the fastener 52.

In an alternate embodiment, the biomaterial 100 is delivered through thelumen 60 without the delivery tube 88. The neck portion 110 serves tosecure the expandable member 90 to the bone screw 52.

As illustrated in FIGS. 2F and 2G, the insert 64 is reintroduced intothe lumen 60. The threads 66, 68 advance the distal end 76 of the insert64 into engagement with the neck portion 110 of the expandable member90. In one embodiment, the neck portion 110 has a generally stiffcone-shape corresponding to the tapered portions 72, 74. The neckportion 110 is preferably constructed from a stiff material that retainsits shape. When the insert 64 is securely coupled to the fastener 52,the tapered portion 74 on the insert 64 compressively engages the neckportion 110 against the tapered portion 72 at the distal end 62 of thelumen 60.

The expanded configuration 108 increases the fixation of the bone screw52 simply by increasing the surface area of engagement with thecancellous bone 84. Fixation is also increased by the shape of theexpandable member 90 in the expanded configuration 108.

In one embodiment, the expanded configuration 108 of the expandablemember 90 includes has at least one dimension 113 greater than acorresponding dimension 112 of the bone screw 52. Correspondingdimension refers to dimensions or features located along an axis offailure (e.g., pull-out direction 118B) of both an orthopedic implantand a fixation system. The at least one dimension 113 reduces the riskthat the fixation system 98 will be pulled through the opening 114 inthe cortical bone 80. In particular, the expanded configuration 108increases the pull-out strength of the bone screw 52, as measuredaccording to ASTM standard F543-02 Annex A3 “Test Method for Determiningthe Axial Pullout Strength of Medical Bone Screws, which is incorporatedby reference.

The transverse dimension 113 (perpendicular to an axis of the lumen 60)of the expandable member 90 and the biomaterial 100 is preferablygreater than the transverse dimension of the bone screw 52. In oneembodiment, the transverse dimension 113 is at least 125%, and morepreferably at least 150%, of the transverse dimension 112 of the bonescrew 52.

Enlarged lower surface 116 of the expandable member 90 augments thefixation of the bone screw 52 against compression force 118A. Enlargedupper surface 120 augment the fixation of the bone screw 52 againsttension force 118B. The attachment of the neck portion 110 to the distalend 62 transfers the compression and tension forces 118A, 118B betweenthe expandable member 90 and the bone screw 52.

The fixation system 98 also effectively resists bending moments 118C. Inembodiments where the expandable member 90 deploys in a non-symmetricalshape, the present orthopedic implant 50 resists torques 118D applied tothe bone screw 52, reducing the risk of the screw 52 backing itself outover time.

The fixation system 98 provides the surgeon with the option to augmentthe fixation of the bone screw 52, without compromising structuralintegrity. The fixation system 98 preferably increases the pull outstrength in direction 118B of the bone screw 52, as measured ASTMstandard F543-02 Annex A3 “Test Method for Determining the Axial PulloutStrength of Medical Bone Screws, by at least 20%, or at least 40%, or byat least 70%, relative to the bone screw 52 alone. Pull out strengthrefers to the tensile force in direction 188B required to fail or removethe bone screw 52 from the bone 84.

In one embodiment, the biomaterial 100 quickly cures or hardens in-situto provide immediate supplemental fixation to the bone screw 52. As usedherein, the term “cure” and inflections thereof, will generally refer toany chemical transformation (e.g., reacting or cross-linking), physicaltransformation (e.g., hardening or setting), and/or mechanicaltransformation (e.g., drying or evaporating) that allows the biomaterialto change or progress from a first physical state or form (generallyliquid or flowable) that allows it to be delivered to the site, into amore permanent second physical state or form (generally solid) for finaluse in vivo. When used with regard to the method of the presentdisclosure, for instance, “curable” can refer to uncured biomaterial,having the potential to be cured in vivo (as by catalysis or theapplication of a suitable energy source), as well as to the biomaterialin the process of curing.

It is not necessary for the biomaterial 100 to harden or cure for thefixation system 98 to secure the bone screw 52. The fixation system 98captures the bone screw 52 within the cancellous bone 82 to resisttension force 118B and bending moment 118C. The biomaterial 100 ispreferably a substantially incompressible material located within afixed space (i.e., cavity 106), to resist compression force 118A. Inembodiments where the biomaterial 100 does not cure or harden in-situ,the patient may require an external structure, such as a brace or cast,to secure the bone 84 until sufficient bone in-growth occurs.

Even after implantation, the fixation system 98 remains separable fromthe bone screw 52. As illustrated in FIG. 2H, if the bone screw 52 needsto be removed from the bone 84 for any reason, the insert 64 is simplyremoved to release the neck portion 110 from the bone screw 52. In theevent that there is residual adhesion between the neck portion 110 andthe bone screw 52, an instrument such as a probe, drill, trocar can beinserted into the lumen 60 as illustrated in FIG. 21C.

The bone screw 52 is then removed from the bone 84 by rotating in thecounter-clockwise direction 111. The implanted fixation system 98 can bereused or abandoned in the bone 84. In an embodiment where thebiomaterial 100 is a bioabsorbable bone growth material, the fixationsystem 98 is substantially absorbed into the bone 84.

The fixation structures disclosed herein, including expandable member90, can be constructed from elastic or inelastic materials that providean optimal combination of such properties as flexibility under staticand dynamic conditions, tensile strength, elongation, tensile modulus,ductility, stability and durability, and compliance. In one embodiment,the expandable member 90 has a pre-determined volume and shapecorresponding to the implantation site, such as disclosed in U.S. Pat.No. 5,972,015 (Scribner et al.), which is hereby incorporated byreference.

In another embodiment, the lateral walls of the expandable member 90 areconstructed from a compliant material (or having a compliance valuesignificantly lower than the delivery pressure of the biomaterial 100 soas to stretch) and the superior and inferior walls 120, 116 arenon-compliant material (or having a compliance value significantlyhigher than the delivery pressure of the biomaterial 100). Consequently,during delivery of the biomaterial 100, the expansion force isessentially applied in lateral direction 122 (outward relative to theaxis of the bone screw 52) to create a flattened oval shape. Thisconfiguration increases the size of the upper and lower surfaces 120,116 to increase fixation.

In one embodiment, the expandable member 90 is constructed from aflexible porous material with pore sizes sufficient to generally retainthe biomaterial 100, but also permit intimate contact between thebiomaterial 100 and the cancellous bone 82, such as for example, thebiocompatible mesh disclosed in U.S. Pat. No. 7,226,481 (Kuslich) andU.S. Patent Publication No. 2009/0024147 (Ralph et al.), which arehereby incorporated by reference. In one embodiment, the expandablemember 90 includes pores in the range of about at least 0.2 millimetersto about 5.0 millimeters. The size of the pores are determined based ona number of factors, such as the viscosity of the biomaterial 100, themaximum delivery pressure of the biomaterial 100, and the like.

In another embodiment, the expandable member 90 is embedded in thebiomaterial 100. For example, the pore sizes permit the biomaterial 100to flow freely into the cavity 106 and the cavity 106 retains thebiomaterial 100.

In one embodiment, the expandable member 90 is a continuous film with aplurality of hole. In order to maximize the contact between thebiomaterial 100 and the cancellous bone 82, the number of openings ispreferably maximized, while the size of an individual opening is limitedto retain the biomaterial 100 in the expandable member 90

The expandable member 90 may be a woven or non-woven structure made frommetal or polymeric fibers. Suitable metals include titanium or one ofits alloys, or stainless steel. Suitable polymeric materials includepolymethyl methacrylate (PMMA), castable thermoplastic polyurethanes,for instance those available under the tradenames CARBOTHANE(Thermedics) ESTANE (Goodrich), PELLETHANE (Dow), TEXIN (Bayer), Roylar(Uniroyal), and ELASTOTHANE (Thiocol), as well as castable linearpolyurethane ureas, such as those available under the tradenamesCHRONOFLEX AR (Cardiotech), BIONATE (Polymer Technology Group), andBIOMER (Thoratec).

In one embodiment, the expandable member 90 is coated with anosteo-conductive tissue scaffold, such as disclosed in U.S. PatentPublication Nos. 2011/0082564 (Liu et al.) and 2010/0268227 (Tong etal.), which are hereby incorporated by reference. The expandable member90 and/or the biomaterial 100 optionally include radiopaque properties.Various configurations of a porous expandable structure are disclosed inU.S. Pat. No. 5,549,679 (Kuslich), which is incorporated by reference.

In alternative embodiments, the expandable member 90 may also be formedout of shape memory alloys (SMA) such as nickel titanius (NiTi) shapememory alloys (Nitinol), whereby the expandable member 90 can beprogrammed to be in the contracted state at one temperature (i.e. eitherbelow or above body temperature) and in the expanded state at or aroundbody temperature. Thus, potentially allowing for self-expansion at adesired target site by merely allowing the expandable member 90 to cometo body temperature. The low elastic modulis, high fatigue, ductile andhigh resistance to wear of NiTi alloys are particularly useful for thepresent expandable member 90.

The biomaterial 100 can be any flowable biocompatible material that canbe delivered through delivery tube 88. In the preferred embodiment, thebiomaterial 100 is a resorbable, bone-growth stimulating compositionthat interacts with the cancellous bone 82 through the porous expandablemember 90. Bone in-growth preferably extends substantially through thechamber 104 of the expandable member 90 so that the biomaterial 100 isall eventually incorporated into the cancellous bone 82.

In one embodiment, the biomaterial 100 is small fragments of anosteogenic sponge composition having enhanced osteoinductive propertiesfor use in bone repair, such as disclosed in U.S. Patent PublicationNos. 2002/0082694 (McKay) and 2010/0255042 (Jennissen et al.), which areincorporated by reference. The fragments of sponge composition aresufficient small and compressible to fit into the lumen of the deliverytube 88. The composition enables increased osteoinductive activity whileretaining a reliable scaffold for the formation of new bone within thechamber 104 of the expandable member 90. Various bioactive load bearingbone graft compositions suitable for use as the present biomaterial 100are disclosed in U.S. Pat. Nos. 5,681,872 (Erbe); 5,914,356 (Erbe); and7,589,133 (Pomrink), which are hereby incorporated by reference. Acalcium phosphate bone void filler sold under the tradenameOsteoVationEX available from Osteomed of Addison, Tex., is suitable foruse as the present biomaterial 100.

The osteogenic factor can be one that stimulates production or activityof osteoblasts and osteoclasts. The factor is preferably a bonemorphogenetic protein (BMP) or a LIM mineralization protein (LMP), orcomprises a nucleotide sequence encoding a BMP or LMP. Recombinant humanBMPs may be commercially obtained or prepared as described and known inthe art, e.g. in U.S. Pat. No. 5,187,076 to Wozney et al.; U.S. Pat. No.5,366,875 to Wozney et al.; U.S. Pat. No. 4,877,864 to Wang et al.; U.S.Pat. No. 5,108,932 to Wang et al.; U.S. Pat. No. 5,116,738 to Wang etal.; U.S. Pat. No. 5,013,649 to Wang et al.; U.S. Pat. No. 5,106,748 toWozney et al; and PCT Patent Nos. WO93/00432 to Wozney et al.; WO94/2693to Celeste et al.; and WO94/26892 to Celeste et al., which are herebyincorporated by reference. Such osteogenic factors are preferablydelivered in conjunction with cells, for example autologous cells fromthe recipient of the implant. Most preferably the vector is delivered inconjunction with autologous white blood cells derived from bone marrowor peripheral blood of the recipient. These cells may be applied to thesponge composition along with the osteogenic factor prior toimplantation.

The biomaterial 100 may be in the form of a flowable putty or paste,such as the bone-growth stimulating composition, such as disclosed inU.S. Patent Publication No. 2006/0204586 (Alexander et al.) and U.S.Pat. No. 7,172,629 (McKay), which are hereby incorporated by reference.U.S. Pat. No. 6,770,695 (Ricci et al.) discloses a bone growthstimulating material with a controlled resorption rate that includes acalcium sulfate compound and a polymer containing particles with asetting agent that is flowable through the delivery tube 88. Thebiomaterial 100 optionally includes radiopaque properties to facilitateimaging. Injectable compositions suitable for use as the biomaterial 100is disclosed in U.S. Patent Publication Nos. 2012/0225972 (Guillermo etal.); 2012/0195982 (Hu); 2012/0107401 (McKay); and 2012/0095463 (Rainset al.), which are hereby incorporated by reference.

In another embodiment, the biomaterial 100 is a flowable carrier matrixincluding collagen sponge, ranging from 1.0 mm to 10 mm in size, wettedwith a fluid, such as morphogen, such as disclosed in U.S. Pat. No.7,671,014 (Beals et al.), which is hereby incorporated by reference. Abulking material may be added to the carrier matrix, such as for examplecollagen-ceramic composite materials, allograft and bio-compatibleceramics or minerals that provide bone in-growth scaffolding.

While not preferred, the biomaterial 100 may also be a bone cement. Bylocating the expandable member 90 distally from the fastener 52 theintegrity of the bone 84 engaged with the threads 58 is not compromised.

The biomaterial 100 may also be an in situ curable polymeric materialsincluding, for example, elongated polymeric materials, polymeric beads,hydrogel materials, fusion promoting materials, autograft bone,allograft bone, xenograft bone, or any combination thereof. Thebiomaterial 100 is preferably bioresorbable, such as for example,poly(lactic acid), poly(glycolic acid), p-dioxanon fibers,polyarylethyl, polymethyl methacrylate, polyurethane, amino-acid-derivedpolycarbonate, polycaprolactone, aliphatic polyesters, calciumphosphate, unsaturated linear polyesters, vinyl pyrrolidone,polypropylene fumarate diacrylate, or mixtures thereof, or otherbiocompatible compounds. A flowable, biodegradable polymer that curesin-situ suitable for use as the biomaterial 100 is disclosed in U.S.Pat. No. 5,990,194 (Dunn et al.), which is hereby incorporated byreference. The biomaterial 100 may also be particles, such as bone graftmaterial, bioceramic beads, and/or crushed bone, and associated deliverydevice disclosed in U.S. Pat. No. 6,620,162 (Kuslich et al.), which isincorporated by reference.

FIG. 3 illustrates a kit 150 for use with an orthopedic implant 152 inaccordance with an embodiment of the present disclosure. The kit 150includes a probe 154 and an inflatable device 156 with an attached filltube 158, both used to pre-form a cavity in the cancellous bone toreceive expandable member 160. In some embodiments, the probe 154 can beconfigured as an expandable drill bit, such as disclosed in U.S. Pat.Nos. 5,693,011 (Onik) and 5,928,239 (Mirza), which are herebyincorporated by reference. These expandable drill bits permit theformation of a cavity with an undercut so that the fixation structurehas a dimension greater than a corresponding dimension of the opening inthe cortical bone along the axis of the pull-out direction.

The expandable device 160 includes neck portion 162 constructed from amaterial with sufficient stiffness to retain its shape when positionedin lumen 164 of the fastener 166. The neck portion 162 preferablyincludes a shape complementary to the shape of the tip 168 on the insert170 and distal opening 172 of the lumen 164.

Optional sleeve 196 includes a distal end 198 sized to fit inside theneck portion 162 (see e.g., FIG. 20B). The sleeve 196 has a diameter tofit in the lumen 164 and serves to guide the tip 168 into the neckportion 162. See FIG. 20C.

In one embodiment, the neck portion 162 is constructed from the sameporous material used to construct the expandable member 160, but istreated with a supplemental material, such as a biocompatible polymer,to increase stiffness. In another embodiment, the neck portion 162 isheat treated to increase stiffness.

Delivery tube 174 preferably includes threaded proximal end 176 toposition stop 178 along its axial length to prevent the distal end 184from penetrating too far into the bone. The proximal end 176 alsoincludes an opening 186 sized to receive tip 180 of biomaterialinjection system 182 containing the biomaterial 100. In one embodiment,the biomaterial injection system 182 is configured with a quantity ofbiomaterial 100 corresponding to the volume of the expandable member160. Alternate biomaterial injection systems are disclosed in U.S. Pat.Nos. 7,544,196 (Bagga et al.) and 8,128,632 (Paris et al.), which arehereby incorporated by reference. Various adapters for coupling abiomaterial injection system to an orthopedic device are disclosed inU.S. Pat. No. 8,231,632 (Jordan et al.), which is hereby incorporated byreference.

FIGS. 4A through 4C illustrate various methods of using the kit 150.FIG. 4A illustrates a method of using the probe 154 provided from thekit 150 to prepare cavity 190 in the cancellous bone 82. After removingthe insert 170, the probe 154 is inserted through the lumen 164. Thebend 194 preferably flexes to permit the probe 154 to fit in the lumen164. The probe 154 is rotated and otherwise manipulated so that tip 192prepares cavity 190 in cancellous bone 82. As used herein, “prepare”refers to compressing, fracturing, cut, drill, displacing, puncturing,and/or remove cancellous bone to at least partially form a cavity toreceive a fixation system.

The expandable member 160 is then positioned on distal end 184 of thedelivery tube 174 and inserted through the lumen 164, as discussedherein. Tip 180 of the biomaterial injection system 182 is fitted on theopening 186, and the plunger 188 is advanced to force biomaterial 100into the expandable member 160. In some embodiments, the pressure of thebiomaterial 100 is sufficient to form and/or increase the size of thecavity 190. The delivery tube 174 is removed and the insert 170 isreengaged with the fastener 166.

FIG. 4B illustrates a method of using the inflatable device 156 providedwith the kit 150 to prepare the cavity 190 in the cancellous bone 82.The inflatable device 156, such as for example a balloon catheter, isdelivered through the lumen 164 and positioned in the cancellous bone82. The delivery tube 158 is used to inflate the inflatable device 156and to form the cavity 190, such as disclosed in U.S. Pat. No. 6,235,043(Reiley et al.), which is hereby incorporated by reference. Theinflatable device 156 is preferably inflated with a liquid, and thevolume of liquid is used as an estimate of the amount of biomaterial 100required to fill the expandable member 160 and the cavity 190. Theliquid and the inflatable device 156 are then removed from the lumen 164and the expandable member 160 is implanted using any of the methodsdisclosed herein.

FIG. 4C illustrate an alternate embodiment in which the inflatabledevice 156 is positioned in the expandable member 160 to form the cavity190 in accordance with an embodiment of the present disclosure. Theinflatable device 156 is positioned inside the expandable member 160 andthe assembly is simultaneously delivered through the lumen 164 and intothe cancellous bone 82.

The inflatable device 156 is preferably inflated with a liquid, whichsimultaneously forms the cavity 190 and expands the expandable member160. The liquid and the inflatable device 156 are then removed from theexpandable member 160 and the fastener 166. The delivery tube 174 isinserted through the lumen 164 and into the expandable member 164 todeliver the biomaterial 100. Finally, the delivery tube 174 is removedand the insert 170 re-engaged with the fastener 166 as discuss herein.

FIG. 5 illustrates an alternate method of coupling an expandable member200 to a fastener 202 in accordance with an embodiment of the presentdisclosure. Neck portion 204 extends up into lumen 206 beyond taperedportion 208 of the fastener 202. In one embodiment, distal end 210 ofthe insert 212 has a diameter greater than shaft 214 so that edges 216facilitate engagement with the neck portion 204. During removal of theinsert 212 during a revision procedure, the edges 216 preferably severthe neck portion 204 near the tapered portion 208 of the fastener 202.

In the illustrated embodiment, the expandable member 200 includesengagement features 218 that penetrate the adjacent cancellous bone 82during delivery of the biomaterial 100. The delivery pressure of thebiomaterial 100 is preferably sufficient to embed the engagementfeatures 218 in the adjacent cancellous bone 82.

FIG. 6 illustrates an alternate method of coupling an expandable member220 to a fastener 222 in accordance with an embodiment of the presentdisclosure. Distal portion 224 of the lumen 226 includes shoulders 228.The neck portion 230 optionally has a shape corresponding to theshoulders 228 or is deformed into that shape when inserted in the lumen226. Distal end 232 of the insert 234 includes a corresponding shapethat captures the neck portion 230 against the shoulders 228.

FIGS. 7A through 7C illustrate an alternate insert 250 with structure252 configured to engage with neck portion 254 of the expandable member256. In the illustrated embodiment, the structure 252 has a generallyhelical shape so that as the insert 250 is rotated in the clockwisedirection 258, the neck portion 254 is drawn upward in direction 262into the lumen 260 and slack is removed from the neck portion 254.Tension at interface 278 between the fastener 276 and the expandablemember 256 increases fixation. FIG. 7C illustrates the neck portion 254cut-away to show the structure 252.

Leading edge 264 of the helical structure 252 has a gradual slope so asto not damage the neck portion 254. Trailing edge 266 of the structure252 preferably include cutting edge 268. If removal of the fastener 276is required, the insert 250 is rotated in the counter-clockwisedirection 270. Cutting edge 268 severs the neck portion 254 of thefixation system 274 to facilitate removal of the fastener 276 from thebone 84.

The present insert 250 with the cutting edge 268 permits the neckportion 254 to extend the entire length of the fastener 268. In oneembodiment, the neck portion 254 extends beyond the head 272 of thefastener 276 (see e.g., FIG. 8B). After the insert 250 is engaged withthe fastener 268 the excess neck portion 254 is cut and removed.

FIGS. 8A and 8B of an orthopedic implant 280 for use with fixationsystem 299 in accordance with an embodiment of the present disclosure.The expandable member 282 includes neck portion 284 that extends beyondhead 286 of the fastener 288.

As illustrated in FIG. 8A, the insert is removed and the expandablemember 282 and delivery tube 290 are inserted through the lumen 292.Check valve 294 is located generally between the expandable member 282and the neck portion 284. The check-valve 294 serves to retain thebiomaterial 100 (see FIG. 8B) in the expandable member 282 and/orprevent the biomaterial 100 from entering the lumen 292. The deliverytube 290 extends through the check valve 294 to delivery biomaterial 100to the expandable member 282.

In one embodiment, the neck portion 284 is modified to make itnon-porous so that the biomaterial 100 does not contact the orthopedicimplant 280. For example, the porous neck portion 284 can be coated witha polymeric material.

After delivery of the biomaterial 100 is completed, the delivery tube290 is removed from the fastener 288. The check-valve 294 retains thebiomaterial 100 in the expandable member 282 and prevents bonding withthe orthopedic implant 280.

In one embodiment, insert 296 attaches proximal end 298 of the elongatedneck portion 284 to the orthopedic implant 280. Any excess neck portion284 extending above the head 286 is removed. In another embodiment, theinserts 170 or 250 can be used to secure the expandable member 282 tothe fastener 288.

The orthopedic implant 280 can be removed from the bone 84 by removingthe insert 296, 170, 250. In one embodiment, the insert 250 (see FIG.7A) is engaged with the fastener 288. As the insert 250 is disengagedthe cutting edge 268 (see FIG. 7A) severs the neck portion 284. Inanother embodiment, a cutting tool, such as a drill bit or trocar suchas illustrated in FIG. 21C, is inserted into the lumen 292 to sever theneck portion 284 from the expandable member 282.

In another embodiment, the check valve 294 is omitted. If thebiomaterial 100 bonds to the sidewalls of the lumen 292, removal can beaccomplished by running a cutting tool down the lumen 292 as illustratedin FIG. 21C.

FIG. 8C illustrates an alternate method of securing the fixation system299 to the fastener 288. A tension force 297 is applied to the neckportion 284 to pull the proximal end 298 to one side, exposing threads295. The tension force 297 reduces any slack in the neck portion 284.The insert 296 is then engaged with the threads 295 to secure the neckportion 284 to the fastener 288.

FIG. 8D illustrates an alternate method of securing the fixation system299 to the fastener 288. Insert 293 is inserted into the neck portion284. Tip 291 of the insert 293 acts to drive biomaterial 100 in the neckportion 284 into the expandable member 282. The check valve 294 is notrequired in this embodiment. The fastener 288 can be removed from thebone 84 using the methods disclosed in connection with FIG. 8B.

FIG. 9A is a side view of an alternate orthopedic implant 300 for usewith fixation system 332 (see FIG. 9B) in accordance with an embodimentof the present disclosure. In the illustrate embodiment, the orthopedicimplant 300 is a cannulated fastener 302 having a head 304, a shank 306with threads 308. Lumen 310 extends from the head 304 to distal end 312.Insert 314 includes threads 316 configured to engage with internalthreads 318 near distal end 312 of the lumen 310.

Locking screw 322 engaged with internal threads 324 located in the head304 of the fastener 302 in order to torsionally lock the head 320 of theinsert 314 to the fastener 302. When located in the orthopedic implant300, the insert 314 substantially seals the lumen 310 (see FIG. 9B).

The insert 314 is configured to torsionally couple to both the head 304and the distal end 312 of the fastener 302. Consequently, the breakingangle, torsion strength, torsion yield strength, insertion torque,self-tapping force, and maximum torque of the fastener 302 combined withthe insert 314, as measured according to ASTM standard F543-07—StandardSpecification and Test Methods for Metallic Bone Screws, is comparableto a solid screw having the same outer dimensions and constructed fromthe same material.

As illustrated in FIG. 9B, the expandable member 326 has been deployedwith the biomaterial 100. The insert 314 is then reintroduced into thelumen 310. The threads 316, 318 advance the distal end 328 of the insert314 into engagement with the neck portion 330 of the expandable member326. The neck portion 330 is shown cut-away to illustrate the engagementwith the threads 316. Locking screw 322 is engaged with the head 304 inorder to secure the head 320 of the insert 314 to the fastener 302.

In one embodiment, reinforcing fibers 334 extend between the expandablemember 326 and the neck portion 330. The reinforcing fibers 334 reduceelastic deformation of the fixation system 332 to create a more directcoupling with the fastener 302. The reinforcing fibers 334 can be thesame or different material used to construct the neck portion 330 andthe expandable member 326. The reinforcing fibers 334 are preferablysubstantially inelastic.

FIG. 10 illustrates acetabular cup assembly 350 secured using a fixationassemblies 352 in accordance with an embodiment of the presentdisclosure. Metal shell 354 of acetabular cup assembly 350 is implantedin acetabulum A using bone screws 356, as is known in the art.

Acetabular cup member 358 is configured to receive a spherical ball B ofa femoral hip joint prosthesis P which has been implanted in a femur F.An acetabular cup assembly suitable for use with the present fixationsystem is disclosed in U.S. Pat. No. 5,549,701 (Mikhail), which ishereby incorporated by reference. If the surgeon determines that thescrews 356 are not sufficiently secure one or more of the presentfixation assemblies 352 are added to the bone screws 356, as discussedabove.

FIG. 11 illustrates a total shoulder prosthesis 380 using a plurality offixation assemblies 382, 384 in accordance with an embodiment of thepresent disclosure. Glenoid implant 386 includes plate 388 secured inthe glenoid cavity 390 of the scapula 391 with a plurality of screws392. The illustrated screws 392 each include fixation assemblies 382such as discussed above. Fixation assembly 382 is also provided for thestem 383 on the glenoid implant 386. Glenoid sphere 394 is configured tobe fitted over the plate 388. A shoulder prosthesis suitable for usewith the present fixation assemblies 382, 384 is disclosed in U.S.Patent Publication 2003/0114933 (Bouttens et al.), which is herebyincorporated by reference.

Humeral implant 396 is secured in medullar canal 398 of the humerus 400using conventional techniques. Fixation system 384 extends into themedullar canal 398, where expandable member 402 is filled withbiomaterial 100, as discussed herein. The humeral implant 396 includes alumen with an insert that releasably secures the fixation system 384, asdiscussed herein. The fixation system 384 can be implanted usingminimally invasive techniques, reducing damage to the bone 400.

Fastener 404, such as for example bone screws or pins, are optionallyengaged with the expandable member 402. The porous nature of theexpandable member 402 is self-healing so the biomaterial 100 does notflow out. The size of the expandable member 402 simplifies locating thefastener 404 relative to the humeral implant 396. The high tensilestrength of the expandable member 402 serves to transfer loads on thehumeral implant 396 across a greater surface area of the bone 84.

The present fixation system 384 can be used with any long bone,including the femur, tibia, and fibula, as well as arm bones includingthe radius, ulna, and humerus. The present expandable member 402 can beused with a variety of intramedullary devices, such as disclosed in U.S.Pat. Nos. 6,551,321 (Burkinshaw et al.); 3,779,239 (Fisher et al.);5,053,035 (McLaren); 6,228,123 (Dezzani); 7,632,277 (Woll et al.); andU.S. Patent Publication Nos. 2006/0200142 (Sohngen et al.); 2006/0100623(Pennig); 2010/0094292 (Parrott), which are hereby incorporated byreference.

FIGS. 12A and 12B are schematic illustrations of a fixation system 420with multiple expandable members 422A, 422B (“422”) connected by neckportions 424A, 424B (“424”) in accordance with an embodiment of thepresent disclosure. The fixation system 420 is optionally a unitarystructure of woven fibers to provide high tensile strength along thelength of the fixation system 420 or a modular structure (see FIG. 13).The present fixation system 420 can be used alone or in combination withanother orthopedic implant.

In the illustrated embodiment, one or more check-valve assemblies 426A,426B, 426C (“426”) are optionally located in the fixation system 420 atvarious transition locations. The check-valve assemblies 426 can besecured to the fixation system 420 by a variety of techniques, such asadhesives, spot welding, compression rings, mechanical fasteners, andthe like.

As illustrated in FIG. 12A, check-valve 426A is positioned to isolateexpandable member 422A. The check-valve 426A permits the biomaterial 100to be delivered through delivery tube 428 under pressure so as todisplace any cancellous bone, without entering the other portions of thefixation system 420.

As illustrated in FIG. 12B, the delivery tube 428 is retracted indirection 430 and the check-valve 426A closes. Biomaterial is optionallydelivered into neck portion 424A. Alternatively, since the neck portion424A typically only operates in tension, no biomaterial is required.Distal end 432 of the delivery tube 428 next positioned in theexpandable member 422B. Check-valves 426B, 426C isolate the biomaterial100 in the expandable member 422B.

The delivery tube 428 is then removed and the neck portion 424B issecured to the orthopedic implant such as discussed herein.

FIG. 13 is an exploded view of a modular expandable member 450 for usein a fixation system in accordance with an embodiment of the presentdisclosure. Expandable member 452A, 452B (“452”) include tubularcouplings 454 with internal threads 456 and optional check-valves 458.The expandable members 452 can be bonded to the couplings 454 using avariety of techniques, such as adhesives, solvent bonding, mechanicaldeformation, mechanical interlock, spot welding, compression rings, or avariety of other techniques. In one embodiment, the expandable members452 are a metal expandable member that is spot welded to metalliccouplings 454.

Extension 460A, 460B (“460”) similarly includes tubular couplings 462with internal threads 464 similar to the internal threads 456. Hollowmembers 464 are provided with external threads 466 that mate with theinternal threads 456, 464, permitting the expandable members 452 to beassembled in a modular fashion.

FIG. 14 illustrates bone plate 540 used in combination with bone screw560 and fixation system 542 to reduce and secure distal radial fractures544 in accordance with an embodiment of the present disclosure. Thefixation system 542 includes multiple chambers 552A, 552B (“552”), suchas illustrated in FIGS. 12 and 13. The embodiment of FIG. 14 isparticularly useful where the cancellous bone is compromised and cannotadequately engage with fasteners 546. A bone plate and implantationmethodology suitable for use with the present fixation system 542 isdisclosed in U.S. Pat. No. 6,440,135 (Orbay et al.), which is herebyincorporated by reference.

In the illustrated embodiment, fastener 548 extends into the bone 550from the opposite side and engages the expandable members 552 to providebi-lateral fixation, without the need of complex mechanisms to align thefastener 548 with holes in the orthopedic implant 540. The expandablemembers 552 are relatively easy targets to hit due to their size. Thepore size in the expandable members 552 is sufficiently small and theweave sufficiently tight that the fasteners 548 are securely engagedwith the fixation system 542. The punctures of the expandable members552 are preferably self-healing, so leakage of the biomaterial isminimized.

FIGS. 15 and 16 illustrate a knotless suture anchor 570 used with afixation system 572 in accordance with an embodiment of the presentdisclosure. Bore 574 is formed in bone 84 in the area where tissue 576is detached from the bone 84. The internal diameter 578 of the bore 574is preferably slightly smaller than external diameter of projections 580on the suture anchor 570.

Suture material 582 is threaded through opening 594 in tissue 576 andsuture anchor 570. A variety of mechanisms can be used to engage thesuture material 582 with the suture anchor 570, such as disclosed inU.S. Patent Publication Nos. 2007/0203498 (Gerber), 2006/0100630 (West,Jr.) and U.S. Pat. Nos. 6,146,406 (Shluzas et al.); 6,770,076(Foerster); 5,505,735 (Li); and 5,571,104 (Li), which are herebyincorporated by reference. The suture anchor 570 is then driven into thebore 574 using driver device 584. Projections 580 mechanically couplewith cortical bone 80.

For some applications, expandable member 586 is optionally insertedthrough lumen 588 in the suture anchor 570 until it is positioned in thecancellous bone 82, as discussed herein. Biomaterial 100 is deliveredinto the expandable member 586 as illustrated in FIG. 16. Proximal end590 of the expandable member 586 is then secured to the suture anchor570 using a releasable fastener. Distal ends 592 of the suture material582 are then tensioned by the surgeon as needed to attach the tissue 576to the bone 84.

FIGS. 17A and 17B illustrate an alternate anchor 600 in which thefixation system 602 is attached directly to the tissue 576 in accordancewith an embodiment of the present disclosure. The anchor 600 isimplanted in the bone 84 and portion 604 of the expandable member 606located in the cancellous bone 82 is filled with biomaterial 100 asdiscussed above. A check-valve structure such as illustrated in FIG. 10Ais preferably located in the anchor 600 to retain the biomaterial 100 inthe portion 604.

Portion 608 of the expandable member 606 extends beyond the anchor 600.In one embodiment, the portions 604 and 608 are a unitary, woven, porousstructure. In another embodiment, the portion 608 is treated with ascaffolding for biological in-growth of the tissue 576, such asdisclosed in U.S. Patent Publication Nos. 2010/0179591 (Saltzman et al.)or 2010/0298937 (Laurencin et al.), which are hereby incorporated byreference.

As illustrated in FIG. 17B, the portion 608 of the expandable member 606is then secured to the tissue 576 using a variety of fasteners 610, suchas sutures, staples, and the like, such as disclosed in U.S. PatentPublication No. 2010/0312275 (Euteneuer et al.), which is herebyincorporated by reference. Various tissue fastening structures can alsobe used to secure the tissue 576 to the portion 608, such as disclosedin U.S. Pat. No. 7,172,615 (Morriss), which is hereby incorporated byreference. Suture material 612 is optionally threaded through theportion 608 and placed under tension to apply tension to the tissue 576relative to the fixation system 602.

FIGS. 18A and 18B illustrate a tissue fastening structure 620 used withfixation system 622 to secure tissue 624 to bone 84 in accordance withan embodiment of the present disclosure. Tissue fastening structure 620includes post 626 that is inserted in bore 628 in cortical bone 80. Tab630 preferably engaged with cortical bone 80 to secure the fasteningstructure 620. Fixation system 622 and biomaterial 100 are deployed intocancellous bone 82 through port 632. Fastener 634 releasably attachesfixation system 622 to the fastening structure 620, to permit futureremoval or revision.

In the illustrated embodiment, the tissue fastening structure 620includes barbs 636 angled opposite tension direction 638 of tissue 624.The surgeon pulls the tissue 624 in direction 640 and engages the barbs636.

FIG. 19 illustrates an alternate tissue fastening structure 650 withfixation system 652 in accordance with an embodiment of the presentdisclosure. Tissue fastening structure 650 includes barbs 654 configuredto engage with tissue 656 as discussed above. In the illustratedembodiment, tissue fastening structure 650 is slidingly engaged withelongated ratcheting member 658 in order to adjust tension on tissue656.

Proximal end 660 of the elongated ratcheting member 658 is secured tobone 84 by fixation system 652. In the illustrated embodiment,expandable member 662 and biomaterial 100 are delivered through portal664 at proximal end 660.

FIG. 20A illustrates an alternate method using the kit 150 of FIG. 3 inaccordance with an embodiment of the present disclosure. Distal end 198of the sleeve 196 is inserted into the neck portion 162. In oneembodiment, the neck portion 162 is temporarily attached to the sleeve196, such as by a low-tack adhesive.

As illustrated in FIG. 20B, the delivery tube 174 is inserted throughthe sleeve 196 and into the expandable member 160, as discussed herein.In the preferred embodiment, the delivery tube 174, sleeve 196, andexpandable member 160 are preassembled in the kit 150.

The delivery tube 174 is removed from the orthopedic implant 152 afterdelivery of the biomaterial 100, as illustrated in FIG. 20C. The insert170 is positioned in the lumen 197 of the sleeve 196. The sleeve 196guides the tip 168 into engagement with the neck portion 162. The sleeve196 also protects the neck portion 162 from damage as the insert 170 isrotated into engagement with the orthopedic implant 152. In anotherembodiment, the sleeve 196 can be used to deliver the biomaterial 100 tothe expandable member 160.

If the orthopedic implant 152 needs to be removed from the patient, theinsert 170 is first removed. The sleeve 196 is removed from the patientalong with the orthopedic implant 152. The act of unscrewing theorthopedic implant 152 from the bone will break any connection betweenthe sleeve 196 and the neck portion 162.

FIGS. 21A through 21C illustrate an orthopedic implant 700 configuredfor use with an optional fixation system 702 (see FIG. 8A) in accordancewith an embodiment of the present disclosure. Neck portion 704 of theexpandable member 706 extends generally the full length of theorthopedic implant 700. Delivery tube 708 is used to inflate theexpandable member 706 and the neck portion 704 with biomaterial 100. Inone embodiment, the delivery tube 708 is retracted during delivery ofbiomaterial 100 fills the entire lumen 710 is filled.

As illustrated in FIG. 21B, the biomaterial 100 substantially fills thelumen 710 of the orthopedic device 700. In the event that thebiomaterial 100 does not bond to the orthopedic implant 700, threads 712for the insert (see e.g., FIG. 1) mechanically interlock with thebiomaterial 100 to secure the fixation device 702 to the orthopedicimplant 700. In the illustrated embodiment, the biomaterial 100 acts asthe insert.

In the illustrated embodiment, the expandable member 706 is tetheredoffset from distal end 714 of the orthopedic implant 700 by segment 716of the neck portion 704. In an alternate embodiment, the expandablemember 706 is in contact with the distal end 714 of the orthopedicdevice 700.

As illustrated in FIG. 21C, the orthopedic device 700 may be removedfrom the bone 84 by inserting a drill bit 718 into the lumen 710 andremoving most of the biomaterial 100. The drill bit 718 preferablyextends past the distal end 714 to sever the segment 716 of the neckportion 704 from the orthopedic implant 700. In this manner thebiomaterial 100 and the expandable member 706 do not interfere withsubsequent removal of the orthopedic implant 700. The orthopedic implant700 is then unscrewed from the bone 84 using conventional techniques.

The expandable member 706 and the biomaterial 100 is abandoned in thebone 84. In embodiments where the biomaterial 100 is a bone growthmaterial, the fixation system 702 will be substantially absorbed intothe bone 84.

FIG. 22 is a flow chart of a method of implanting an orthopedic implantin a bone in accordance with an embodiment of the present disclosure.The orthopedic implant is implanted in the bone so that a proximalportion of the orthopedic implant is accessible and a distal portion ofthe orthopedic implant extends through cortical portions and intocancellous portions of the bone (750). Fixation of the orthopedicimplant is evaluated (752). An insert located in the orthopedic implantis removed to expose at least one lumen extending from the proximalportion to the distal portion (754). At least one expandable member isinserted through the lumen and positioning the expandable member in thecancellous bone (756). A delivery tube is inserted through the lumen andinto fluid communication with a chamber in the expandable member (758).A flowable biomaterial is delivered through the delivery tube and intothe expandable member located in the cancellous bone (760). Theexpandable member is inflated to an expanded configuration with at leastone dimension greater than a corresponding dimension on the orthopedicimplant in the bone (762). The insert is secured in the lumen toreleasably attach the fixation system to the orthopedic implant (764).

FIG. 23A illustrates an alternate insert 800 for use with a fixationsystem 802 in accordance with an embodiment of the present disclosure.The expandable member 804 is implanted using the techniques disclosedherein, such as for example as shown in FIGS. 2F, 7C, 8B. Insert 800includes a threaded tip 806 configured to extend through the lumen 808and into the expandable member 804 and biomaterial 100. The threaded tip806 can be used to supplement the attachment between the fastener 810and the expandable member 804, or can be the sole attachment mechanism.

To remove the fastener 810 the insert 800 is removed. The fastener 810is then removed from the bone 84 using conventional techniques. All thatremains of the fixation system 802 is the biomaterial 100 and theexpandable member 804.

FIGS. 23C and 23D illustrate an alternate fixation system 802A in whichthe biomaterial 100 is injected through the lumen 808 directly intocavity 801 formed in the cancellous bone 82, without the expandablemember 804. The insert 800 includes a threaded tip 806 that engage withthe biomaterial 100. In one embodiment, reinforcing fibers 803 are mixedwith the biomaterial 100 that engage with the threaded tip 806 toincrease fixation and reduce the flow of the biomaterial 100 within thecancellous bone 82.

The reinforcing fibers 803 can be made from any of the materials used toconstruct the fixation structure discussed herein. In one embodiment,the reinforcing fibers 803 are made from a biocompatible polymer, suchas for example PEEK. The length of the reinforcing fibers 803 can varybut are typically in the range of about 5 millimeters to about 25millimeters. A suitable bone substitute material with reinforcing fibersis disclosed in U.S. Pat. Nos. 8,192,835 (Chi) and 8,003,133 (Li etal.), which are hereby incorporated by reference.

The embodiment of FIGS. 23C and 23D is particularly useful for smallfasteners 810 because the biomaterial 100 can be injected through thelumen 808 without a delivery tube and no expandable member 804 needs topass through the lumen 808.

FIGS. 24A through 24C illustrate an orthopedic implant 850 with one ormore alternate fixation structures 852 in accordance with an embodimentof the present disclosure. The fixation structures 852 are elongatedsegments of biocompatible material positioned in lumen 854. Theelongated segment can be configured as one or more filaments, ribbonshaped structure, a sling, a braided structure, and the like.

In one embodiment, the fixation structure 852 is a single segment ofbiocompatible material positioned in the lumen 854 so that centerportions 856 is located in the cavity 858 in the cancellous bone 82. Thefixation structure 852 can be made from any of the material disclosedherein, including mono-filaments, woven or non-woven materials, mesh,porous and non-porous sheet materials, suture material, and the like.

Proximal ends 860A, 860B of the fixation structures 852 are bothpreferably located outside the lumen 854 above the head 862. Deliverytube 864 is used to deliver the biomaterial 100 into the cavity 858. Thebiomaterial 100 secures the center portion 856 in the cavity 858. In oneembodiment, the center portion 856 of the fixation structure 852 isembedded in the biomaterial 100.

As illustrated in FIG. 24B, the biomaterial 100 substantially fills thelumen 854 of the orthopedic device 850. In the event that thebiomaterial 100 does not bond to the orthopedic implant 850, threads 866for the insert (see e.g., FIG. 1) mechanically interlock with thebiomaterial 100 to secure the fixation structure 852 to the orthopedicimplant 850. In the illustrated embodiment, the biomaterial 100 acts asthe insert. In another embodiment, the biomaterial 100 is locatedprimarily in the cavity 858 and an insert such as illustrated in FIG. 1is used to secure the fixation structure 852 to the orthopedic implant850.

As illustrated in FIG. 24C, the orthopedic device 850 may be removedfrom the bone 84 by inserting a drill bit 718 into the lumen 854 andremoving most of the biomaterial 100. The drill bit 718 preferablyextends past the distal end 868 to sever the fixation structure 852 fromthe orthopedic implant 850. In this manner the biomaterial 100 and thefixation structure 852 do not interfere with subsequent removal of theorthopedic implant 850. The orthopedic implant 850 is then unscrewedfrom the bone 84 using conventional techniques.

The fixation structure 852 and the biomaterial 100 is abandoned in thebone 84. In embodiments where the biomaterial 100 is a bone growthmaterial, the fixation structure 852 will be substantially absorbed intothe bone 84.

FIG. 25A illustrates an orthopedic implant 880 with a plurality ofalternate fixation structures 882 in accordance with an embodiment ofthe present disclosure. The fixation structures 882 can be a variety ofelongated structures made from a biocompatible material positioned inlumen 884 that is capable of transferring tensile loads between thebiomaterial 100 in cavity 888 and the implant 880.

In one embodiment, the fixation structure 882 is a rigid or semi-rigidpolymer member with one or more barbs 886 positioned in the cavity 888in the cancellous bone 82. The barbs 886 are designed to fold inwardduring insertion into the lumen 884, and hence, can have an expandedconfiguration larger than the lumen 884. The barbs 886 are embedded inthe biomaterial 100. Alternate designs for the fixation structures 882include ribbons or cylindrical structures of a biocompatible mesh orfabric, segments of woven or non-woven material, suture material, andthe like.

An insert or the biomaterial 100 can be used to secure proximal ends 890of the fixation structures 882 to the orthopedic implant 880. Thebiomaterial 100 can be delivered to the cavity 888 using a delivery tube(see e.g., FIG. 24A) or through the lumen 884.

In the embodiment of FIG. 25B, the lumen 884 is used to deliver thebiomaterial 100 into the cavity 888. The lumen 884 is also filled withbiomaterial 100. The fixation structures 882 can be inserted into thelumen 884 and cavity 888 either before or after delivery of thebiomaterial 100. Removal of the implant 880 is accomplished by running acutting tool through the lumen 884 to remove the biomaterial and tosevere the fixation structures 882 from the biomaterial 100 in thecavity 888 (see e.g., FIG. 24C). The severed portion of the fixationstructures 882, including the barbs 886, are abandoned with thebiomaterial 100 in the cavity 888.

FIG. 25C illustrates the orthopedic implant 880 with the biomaterial 100filling the lumen 884 and the cavity 888. In the illustratedconfiguration the cured biomaterial 100 optionally acts as the fixationstructure 882. For some small bone applications the cured biomaterial100 may provide sufficient fixation. A shear plane, however, exists atthe tip 881 of the orthopedic implant 880 where the biomaterial 100 islikely to fracture. Adding reinforcing fibers to the biomaterial 100(see e.g., FIG. 23C) increases the fixation strength of the curedbiomaterial 100 at the shear plane.

FIG. 25D illustrates a preferred configuration with fixation structure882 inserted through the lumen 884 and into the biomaterial 100 in thecavity 888. The fixation structure 882 includes tines or barbs 886 asdiscussed herein that fold inward during insertion through the lumen 884and expand in the cavity 888 to increase fixation.

In the illustrated embodiment a sheath 883 prevents adhesion with thebiomaterial 100 located within the lumen 884 to the fixation structure882. As a result, tensile loads are distributed over length 887 of thefixation structure 882 between cap 885 and the tines 886. The improvedstress-strain properties of the fixation structure 882 due to the sheath883 increases fixation of the orthopedic implant 880. The cap 885 alsolimits the degree of penetration of the fixation structure 882 into thecavity 888. In one embodiment, the fixation structures 882 are coded(e.g., color coded) to correspond to the bone screws 880 of a particularlength so that optimal penetration into the cavity 888 is achieved.

FIGS. 26A and 26B illustrate an orthopedic implant 900 with an alternatefixation structures 902 in accordance with an embodiment of the presentdisclosure. The fixation structures 902 includes a proximal end 904configured to engage with distal end 906 of the insert 908. In oneembodiment, the fixation structure 902 is attached to the insert 908,such as by complementary threads.

A variety of structures can be attached to, or molded onto, theproximate end 904. In the illustrated embodiment, one or more elongatedmembers 910 are attached to the proximal end 904. In the preferredembodiment, the elongated members 910 are formed in a collapsedconfiguration 912 sized to fit in the lumen 914.

As the fixation structure 902 is inserted into the cavity 918 the distalends 916 of the elongated members 910 engage with the cancellous bone 82and are biased to expanded configuration 920 illustrated in FIG. 26B.The elongated members 910 are embedded in the biomaterial 100.

FIGS. 27A through 27D illustrate a suture anchor 950 used with afixation structure 952 in accordance with an embodiment of the presentdisclosure. Bore 954 is formed in bone 84 in the area where tissue 956is detached. The internal diameter 958 of the bore 954 is preferablyslightly smaller than an external diameter of projections 960 on thesuture anchor 950. Cavity 962 is then prepared at the distal end of thebore 954 using any of the techniques discussed herein.

As illustrated in FIG. 27B, fixation structure 952 is positioned in thecavity 962 and filled with biomaterial 100 as discussed herein. Valve964 retains the biomaterial 100 in the expandable member 966 of thefixation structure 952. Neck portion 968 extends from the expandablemember 966 and through the bore 954. Distal portions 970A, 970B (“970”)of the neck portion 968 extend beyond the bone 84.

The neck portion 968 can be a hollow cylindrical sleeve, one or morereinforcing fibers, one or more ribbons of a flexible material, or avariety of other structures configured to carry a tensile load. In theillustrated embodiment, the distal portions 970 are ribbon structures ofa mesh material that promotes tissue in-growth.

As illustrated in FIG. 27C, the suture anchor 950 is then driven intothe bore 954. Projections 960 mechanically couple with the neck portion968 and the cortical bone 80. In one embodiment, the projections 960penetrate the neck portion 968 and engage with the cortical bone 80.Suture material 972 is then tensioned to draw the tissue 956 against thebone 84 and to provide the desired amount of tension on the tissue 956.

As illustrated in FIG. 27D, the distal portions 970 are positioned onthe tissue 956 and attached by fasteners 974, such as sutures, staples,and the like. In one embodiment, the fasteners 974 capture the tissue956 between the two distal portions 970A, 970B. Over time, the tissue956 preferably fuses with the distal portions 970. The distal portions970 transfer a substantial portion of the load on the tissue 956 to theexpandable member 966.

In an alternate embodiment illustrated in FIG. 27E, the suture anchor950 is assembled with the fixation structure 952 ex vivo. The assemblyof the suture anchor 950 and the fixation structure 952 aresimultaneously inserted into the bore 954. The biomaterial 100 is thendelivered to a lumen in the suture anchor 950 (see e.g., FIG. 16). Theprocedure is then completed as illustrated in FIGS. 27C and 27D.

FIGS. 28A and 28B illustrate an alternate combination of suture anchors1000 and fixation structures 1002 in accordance with an embodiment ofthe present disclosure. The suture anchors 1000 are positioned in thebone 84 using conventional techniques. Suture material 1004 is thentensioned to draw the tissue 1006 against the bone 84 and to provide thedesired amount of tension on the tissue 1006. The suture anchors 1000serve to secure the tissue 1006 in the desired configuration while thefixation structures 1002 are implanted.

Bore 1008 is formed in bone 84 near the suture anchor 1000. Cavity 1010is then prepared at the distal end of the bore 1008 to receive thefixation structure 1002 as discussed herein.

As illustrated in FIG. 28B, fixation structure 1002 is positioned in thecavity 1010 and filled with biomaterial 100 as discussed herein. Valve1014 retains the biomaterial 100 in the expandable member 1016 of thefixation structure 1012. Neck portion 1018 extends from the expandablemember 1016 and out through the bore 1008. Distal portion 1020 of theneck portion 1018 extend beyond the bone 84. The distal portion 1020 isthen positioned on the tissue 1006 and attached fasteners 1022, such assutures, staples, and the like.

As illustrated in FIG. 28C, a pair of fixation structures 1002 areimplanted in the bone 84 and the distal portions 1020A, 1020B areattached to the tissue 1006 using fasteners 1022. Over time, the tissue1006 preferably fuses with the distal portions 1020.

FIGS. 29A through 29C illustrate bone plate 1050 used in combinationwith bone screws 1052 and fixation structures 1054 in accordance with anembodiment of the present disclosure. In the illustrated embodiment, aplurality of bone screws 1052 are used to secure the bone plate 1050 tothe bone 84. The initial fixation provided by the bone screws 1052 serveto position the bone plate 1050 and secure any bone fragments in thedesired configuration.

Bore 1056 is then formed through openings 1066 in the bone plate 1050and into the bone 84 for each fixation structure 1054. Cavity 1058 isformed at the distal end of each bore 1056. A fixation structure 1054 ispositioned in each cavity 1058 and filled with biomaterial 100 asdiscussed herein. Valves 1060 preferably retains the biomaterial 100 inthe expandable members 1062 of the fixation structures 1054. Neckportions 1064 extend from the expandable members 1062 and out throughopenings 1066 in the bone plate 1050. In the preferred embodiment, theneck portions 1064 are one or more discrete tension members.

As best seen in FIG. 29C, the neck portions 1064 are positioned in slots1068 in the openings 1066 so as to not interfere with implantation ofthe bone screws 1052. Bone screws 1052 are inserted through the openings1066 and into the bone 84. The threads 1070 engage with both the bone 84and the neck portions 1064. The threads 1070 compress the neck portions1064 into the bone 84. The heads 1072 of the bone screws 1052 secure theneck portions 1064 to the bone plate 1050. Consequently, the fixationstructures 1054 serve to secure the bone plate 1050 to the bone 84.

In one embodiment, one or more secondary fasteners 1076 are engaged withthe bone 84 and the expandable members 1062 to provide bi-lateralfixation. The expandable members 1062 are relatively easy targets to hitdue to their size. The pore size in the expandable members 1062 issufficiently small and the weave sufficiently tight that the fasteners1076 are securely engaged with the fixation system 1054. The puncturesof the expandable members 1062 are preferably self-healing, so leakageof the biomaterial is minimized.

FIG. 30 illustrates bone plate 1100 used in combination with bone screws1102 and fixation structures 1104 to reduce and secure distal radialfractures 544 in accordance with an embodiment of the presentdisclosure. A bone screws 1102 are used to secure the bone plate 1100 tothe bone 84. The initial fixation provided by the bone screws 1102 serveto position the bone plate 1100 and secure any bone fragments in thedesired configuration.

Bores 1106 are then formed through openings 1114 in the bone plate 1100and in the bone 84 for each fixation structure 1104. Cavities 1108 areformed at the distal end of each bore 1106. A fixation structure 1104 ispositioned in each cavity 1108 and filled with biomaterial 100 asdiscussed herein. Neck portions 1110 extend from the expandable members1112 and out through openings 1114 in the bone plate 1100.

In one embodiment, fasteners 1118 are then engaged with the openings1114 to secure the neck portions 1110 to the bone plate 1100. In anotherembodiment, the biomaterial 100 fills the opening 1114 to secure theneck portion 1110 to the bone plate 1100. In one embodiment, one or moresecondary fasteners 1120 are engaged with the bone 84 and the expandablemembers 1112 to provide bi-lateral fixation.

FIGS. 31A through 31C are directed to an alternate fixation structure1150 that is positioned in the cancellous bone 82 with the orthopedicimplant 1152 removed in accordance with an embodiment of the presentdisclosure. In some embodiments, the orthopedic implant 1152 may nothave a lumen or the lumen may be too small to insert a fixationstructure. For those situations the orthopedic implant 1152 is removedfrom the bone 82. Cavity 1154 is formed to receive expandable member1156. In the illustrated embodiment, the cavity 1154 is formed near thebottom of the bore 1158 created for the orthopedic implant 1152.

As illustrated in FIG. 31B, the fixation structure 1150 is positioned inthe cavity 1154. In the preferred embodiment, the fixation structure1150 is self-expanding so as to substantially conform to the cavity1154. In another embodiment, the biomaterial 100 is delivered to thefixation structure 1150 before the orthopedic implant 1152 isreintroduced into the bore 1158. In the illustrated embodiment, thefixation structure 1150 include neck portion 1160 shaped to couple withdistal end 1162 of the orthopedic implant 1152.

As illustrated in FIG. 31C, the orthopedic implant 1152 is thenreintroduced into the bore 1158 until distal end 1162 engages with theneck portion 1160. The distal end 1162 preferably compresses the neckportion 1160 into engagement with the cancellous bone 82. Thebiomaterial 100 is optionally delivered to the fixation structure 1150through lumen 1164.

Insert 1170 is inserted through the lumen 1164 and into the biomaterial100 in the expandable member 1156. The fixation structure 1170 includestines or barbs 1172 that fold inward during insertion. The tines 1172preferably engage with the mesh structure of the expandable member 1156.

Sheath 1174 preferably surrounds the fixation structure 1170 to preventadhesion with the biomaterial 100. As a result, tensile loads aredistributed over length of the fixation structure 1170 between cap 1176and the tines 1172. The orthopedic implant 1152 can be removed using thetechniques discussed in connection with FIG. 25D.

Example 1

Four identical fasteners were tested according ASTM standard F543-02Annex A3 “Test Method for Determining the Axial Pullout Strength ofMedical Bone Screws. The test was performed on a solid rigidpolyurethane foam 40 millimeters×130 millimeters×180 millimeters blockwith a density of 20 pounds made according to Specification F1839,purchased from www.sawbones.com as product number 1522-03.

The fasteners had an outside diameter of about 9.0 millimeters with anoutside threaded length of about 17 millimeters. The lumen had an insidediameter of about 6.0 millimeters.

Four pilot holes about 8.0 millimeters in diameter were drilledcompletely through the test block. A fastener was secured in each of thepilot holes. A cavity was formed behind the fasteners for Samples C andD using a wire with a bent tip attached to a cordless drill and insertedthrough the lumen of the fasteners. The drill was run at a moderatespeed for about 20 seconds for each Sample.

Samples A and B were controls, without any fixation structure. Samples Cand D included a fixation structure configured as an expandable memberand constructed from a light gauze cotton mesh. The expandable memberswere inserted through the lumens and into cavities formed in the testblock. Neck portions of the expandable members were located in thelumens of the fasteners.

The expandable members of Sample C was filled with a 30-minute epoxyresin and Sample D was filled with an expanding construction foam. Sincethe pilot holes extended through the entire thickness of the test blockit was possible to view the delivery of the epoxy and form.

A 0.25-20 machine screws were threaded into the lumens of the controlfasteners and the test fasteners to secure the neck portions of theexpandable members to the fasteners. The heads of the machine screwswere the attachment points for the pull-out test.

Table 1 below shows the results of the pull-out tests. The percentchange is calculated relative to the average of control Samples A and B.

TABLE 1 Pull-out Force Percent Change re: Sample Description (Newtons)Average Control A Control 1312 Control B Control 1342 Control C MeshBag/Epoxy 1798 35.5% increase D Mesh Bag/Expandable 1574 18.6% increaseFoam

The failure mode for Samples A through D was for the test block tofracture around the screws.

Example 2

Four fasteners were tested according ASTM standard F543-02 Annex A3“Test Method for Determining the Axial Pullout Strength of Medical BoneScrews, to evaluate a fixation structure having a ribbon shape.

The test was performed on a solid rigid polyurethane foam 40millimeters×130 millimeters×180 millimeters block with a density of 20pounds made according to Specification F1839, purchased fromwww.sawbones.com as product number 1522-03.

Pilot holes for Samples E and F had a diameter of about 6.3 millimetersand pilot holes for Samples G and H had a diameter of about 4.5millimeters.

The fasteners for Samples E and F had an outside diameter of about 6.0millimeters with an outside threaded length of about 11.0 millimeters.The lumen had an inside diameter of about 5.0 millimeters.

The fasteners for Samples G and H had an outside diameter of about 5.0millimeters with an outside threaded length of about 9.0 millimeters.The lumen had an inside diameter of about 4.0 millimeters.

A cavity was formed behind the fasteners for Samples E and H using abent wire attached to a cordless drill inserted through the lumen of thefasteners. The drill was run at a moderate speed for about 20 seconds.

Samples F and G were controls, without any fixation structure. Samples Eand H included a fixation structure constructed from a ribbon lightgauze cotton mesh. The fixation structures were inserted through thelumens so the center portions of the gauze ribbons were located incavities formed in the test block. Distal ends of the gauze meshextended out of the tops of the fasteners and were folded down againstthe surface of the test block. A 30-minute epoxy resin was injectedthrough the lumens of the fasteners for Samples E and H.

Appropriate sized machine screws were threaded into the lumens of thefasteners. The machine screws secured the distal ends of theribbon-shaped fixation structure to the fasteners in Samples E and H.The heads of the machine screws were the attachment points for thepull-out test.

Table 2 below shows the results of the pull-out tests. The percentincrease in pull-out force for Sample E is measured relative to controlSample F. The percent increase in pull-out force for Sample H ismeasured relative to control Sample G.

TABLE 2 Pull-out Force Percent Change re: Sample Description (Newtons)Control Samples E Mesh Sling/Epoxy 1278 93.3% increase F Control 661Control G Control 426 Control H Mesh Sling/Epoxy 932 118% increase

Example 3

Three fasteners were tested according ASTM standard F543-02 Annex A3“Test Method for Determining the Axial Pullout Strength of Medical BoneScrews, to evaluate a fixation structure having a ribbon shape.

The test was performed on a solid rigid polyurethane foam 40millimeters×130 millimeters×180 millimeters block with a density of 20pounds made according to Specification F1839, purchased fromwww.sawbones.com as product number 1522-03.

Pilot holes for Samples I, J, and K with a diameter of about 6.0millimeters were drilled into the test block at a depth of about 2× thelength of the fasteners, about 22 millimeters.

The fasteners for Samples I, J, and K had an outside diameter of about6.0 millimeters with an outside threaded length of about 11.0millimeters. The lumen had an inside diameter of about 5.0 millimeters.

A cavity was formed behind the fasteners for Samples J and K using abent wire attached to a cordless drill inserted through the lumen of thefasteners. A generally cylindrical cavity was formed having a height ofabout 10 millimeters with a diameter of about 10 to about 12millimeters.

Sample I was control, without any fixation structure.

Sample J included a fixation structure constructed from a ribbon lightgauze cotton mesh. The fixation structures were inserted through thelumens so the center portions were located in cavities formed in thetest block. Distal ends of the gauze mesh extended out of the tops ofthe fasteners and were folded down against the surface of the testblock.

Sample K included a fixation structure was configured as an expandablemember constructed from a light gauze cotton mesh. The expandable memberwas inserted through the lumen and located in cavity formed in the testblock. The neck portion of the gauze mesh extended out of the tops ofthe fasteners.

For Samples J and K, a 30-minute epoxy resin was injected through thelumens of the fasteners and into the cavity.

Appropriate sized machine screws were threaded into the lumens of thefasteners. The machine screws secured the distal ends of theribbon-shaped fixation structure to the fasteners in Samples I, J, andK. The heads of the machine screws were the attachment points for thepull-out test.

Table 3 below shows the results of the pull-out tests. The percentchange in pull-out force for Samples J and K is calculated relative tocontrol Sample I.

TABLE 3 Pull-out Force Percent Change re: Sample Description (Newtons)Control Sample I Control 748 Control J Mesh Sling/Epoxy 1281 71.2%increase K Mesh Bag/Epoxy 1050 40.3% increase

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within the embodiments of the disclosure.The upper and lower limits of these smaller ranges which mayindependently be included in the smaller ranges is also encompassedwithin the embodiments of the disclosure, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either both of those includedlimits are also included in the embodiments of the present disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the embodiments of the present disclosure belong.Although any methods and materials similar or equivalent to thosedescribed herein can also be used in the practice or testing of theembodiments of the present disclosure, the preferred methods andmaterials are now described. All patents and publications mentionedherein, including those cited in the Background of the application, arehereby incorporated by reference to disclose and describe the methodsand/or materials in connection with which the publications are cited.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

Other embodiments of the disclosure are possible. Although thedescription above contains much specificity, these should not beconstrued as limiting the scope of the disclosure, but as merelyproviding illustrations of some of the presently preferred embodimentsof this disclosure. It is also contemplated that various combinations orsub-combinations of the specific features and aspects of the embodimentsmay be made and still fall within the scope of the present disclosure.It should be understood that various features and aspects of thedisclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed embodiments ofthe disclosure. Thus, it is intended that the scope of the presentdisclosure herein disclosed should not be limited by the particulardisclosed embodiments described above.

Thus the scope of this disclosure should be determined by the appendedclaims and their legal equivalents. Therefore, it will be appreciatedthat the scope of the present disclosure fully encompasses otherembodiments which may become obvious to those skilled in the art, andthat the scope of the present disclosure is accordingly to be limited bynothing other than the appended claims, in which reference to an elementin the singular is not intended to mean “one and only one” unlessexplicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment(s) that are known to those ofordinary skill in the art are expressly incorporated herein by referenceand are intended to be encompassed by the present claims. Moreover, itis not necessary for a device or method to address each and everyproblem sought to be solved by the present disclosure, for it to beencompassed by the present claims. Furthermore, no element, component,or method step in the present disclosure is intended to be dedicated tothe public regardless of whether the element, component, or method stepis explicitly recited in the claims.

What is claimed is:
 1. A fixation system configured to releasably securean orthopedic implant to a bone, the orthopedic implant having at leastone lumen extending from a proximal portion to a distal portionconfigured to extend through cortical portions and into cancellousportions of the bone, the fixation system comprising: a flowablebiomaterial configured to flow through the lumen into the cancellousportion of the bone in an expanded configuration comprising at least onedimension greater than a corresponding dimension on the orthopedicimplant located generally along a pull-out direction of the orthopedicimplant; and an insert configured to be inserted through the lumen andinto engagement with the flowable biomaterial located in the cancellousportion of the bone, such that the orthopedic implant is detachable fromthe biomaterial in the cancellous portion of the bone to facilitatesubsequent removal of the orthopedic implant from the bone.
 2. Thefixation system of claim 1 comprising at least one expandable memberpositioned in the cancellous bone near a distal portion of theorthopedic implant configured to receive the biomaterial and to expandto the expanded configuration in the cancellous bone.
 3. The fixationsystem of claim 2 wherein the expandable member is configured to beinserted through the lumen and into the cancellous bone.
 4. The fixationsystem of claim 2 wherein the expandable member comprises a porousstructure with openings sized to permit intimate contact between thebiomaterial and the cancellous bone.
 5. The fixation system of claim 2wherein the expandable member includes a neck portion configured toextend through the lumen and to be secured to the orthopedic implant bya fastener.
 6. The fixation system of claim 2 comprising at least onecheck-valve assembly on the expandable member configured to retain theflowable biomaterial in the expandable member.
 7. The fixation system ofclaim 2 wherein the expandable member includes a neck portion and theorthopedic implant extends at least partially in the neck portion. 8.The fixation system of claim 7 wherein the orthopedic implant compressesthe neck portion into engagement with the cancellous portion of thebone.
 9. The fixation system of claim 1 wherein the expandedconfiguration includes at least one transverse dimension perpendicularto a pull-out direction that is at least 125% of the orthopedic implant.10. The fixation system of claim 1 comprising reinforcing fibers mixedwith the biomaterial to increase fixation between the insert and thebiomaterial located in the cancellous bone.
 11. The fixation system ofclaim 1 comprising a sheath surrounding at least a portion of theinserted that reduces adhesion with the biomaterial.
 12. The fixationsystem of claim 1 wherein biomaterial in the lumen secures the insert tothe orthopedic implant.
 13. The fixation system of claim 1 wherein thebiomaterial comprises a resorbable, bone-growth stimulating compositionthat interacts with the cancellous bone through openings in the firstexpandable member.
 14. A fixation system configured to releasably securean orthopedic implant to a bone, the orthopedic implant having at leastone opening adjacent a bore formed in a cortical portions of the bone,the fixation system comprising: at least one expandable memberconfigured to be inserted through the bore and into cancellous portionof the bone; a flowable biomaterial configured to flow through the boreto inflate the expandable member to an expanded configuration located inthe cancellous bone, the expanded configuration comprising at least onedimension greater than a corresponding dimension of the bore; and afastener configured to releasably attach the expandable member to theorthopedic implant, such that the expandable member is detachable fromthe orthopedic implant to facilitate subsequent removal of theorthopedic implant from the bone.
 15. The fixation system of claim 14wherein the expandable member includes a neck portion configured toextend through the opening and to be secured to the orthopedic implantby the fastener.
 16. The fixation system of claim 14 wherein thefastener comprises a curable biomaterial located in the opening.
 17. Afixation system for securing tissue to bone, the fixation systemcomprising: at least one fixation structure configured to be insertedthrough a bore and into a cancellous portion of the bone, the fixationstructure comprising an expandable member and a neck portion configuredto extend through the bore and away from the bone; a flowablebiomaterial configured to flow through the bore to inflate theexpandable member to an expanded configuration located in the cancellousbone, the expanded configuration comprising at least one dimensiongreater than a corresponding dimension of the bore; at least onecheck-valve assembly on the expandable member configured to retain theflowable biomaterial in the expandable member; and one or more fastenersconfigured to secure the neck portion to the tissue.
 18. The fixationsystem of claim 17 comprising: a suture anchor configured to implant inthe bone; and suture material coupled with the suture anchor, whereinthe suture material is configured to engage with the tissue and toprovide the desired amount of tension on the tissue.
 19. The fixationsystem of claim 18 wherein the suture anchor is configured to be locatedin the bore with the neck portion.